UL Solutions launches AC bidirectional EV charger certification program

A new certification program could make it cheaper for electric vehicles to send power back to the home or grid. UL Solutions, a testing and safety certification company, has opened testing for equipment built to a new standard called UL 1741 Supplement SC, which covers "bidirectional" EV chargers that let power flow both ways between a car and a home's wiring. This is different from vehicle-to-grid systems already sold by companies like dcbel, Sigenergy, and Wallbox, which use direct current (DC) and require an extra external inverter. The new AC-based approach works with cars that have their own built-in bidirectional inverter, skipping the external inverter and likely lowering equipment costs.

The standard took over a decade to develop, building on a separate rule called SAE J3072 that lets cars and chargers from different manufacturers work together. In Europe, similar AC vehicle-to-grid technology is already running: automakers like Renault and BMW have paired it with low-cost home chargers, and a fleet in Utrecht, Netherlands, uses it to send extra solar power back into the local grid.

For homeowners, this doesn't mean new equipment is on shelves yet, but it clears a regulatory path in the US for cheaper bidirectional chargers to reach the market. If you already have solar panels or are considering an EV, this is the kind of technology that could eventually let your car's battery power your home during an outage or send stored energy back to the grid.